1. Field of the Invention
The present invention relates to a laser beam relay unit for use with a laser beam machine composed of a combination of an articulated robot and a laser oscillator and, more particularly, to a laser beam relay unit using air-cooled reflecting mirrors and having a simple construction.
2. Description of the Related Art
Laser beam machines in which a robot and a laser oscillator are combined are now widely used for welding or the heat treatment of metals. This is because the positioning accuracy of robots has been significantly improved and a laser oscillator can be combined with a commercially available robot to construct a laser beam machine.
With such a laser beam machine, a laser beam must be conducted from a laser oscillator to a wrist along an arm of a robot, and accordingly, a laser beam relay unit must be used to shift the direction of the laser beam somewhere along the path of the beam.
Reflecting mirrors used with the laser beam relay unit absorb a percentage of the laser energy, and therefore, the reflecting mirrors generate heat and become deformed; in some circumstances the thin reflecting films coated on the reflecting mirrors may be destroyed. Accordingly, the reflecting mirrors are usually cooled with water.
Preferably, however, water is not used with robots, because when water is used with a robot, water leakages may occur and water might penetrate the mechanism of the robot, such as the joints, and thus cause unnecessary failures.